static void runQuickSort(int[] a, int N, int approxNumThreads) throws InterruptedException {
Global.shuffleArray(a);
double timePassed = System.currentTimeMillis();
Global.allThreads = new ArrayList<quicksortThread>();
quicksortThread main_qsth =
new quicksortThread(
a,
0,
N - 1,
(int) (N / (double) (approxNumThreads / 1.95)),
false); // 1.95 was calculated approximately; it's got to do with the log of the
// quicksort, and is the average branching factor??
Global.allThreads.add(main_qsth);
main_qsth.start();
boolean done = false;
int thcount = 1;
while (!done) {
done = true;
thcount = Global.max(thcount, Global.allThreads.size());
for (int i = 0; i < Global.allThreads.size(); i++) {
if (Global.allThreads.get(i) != null
&& Global.allThreads.get(i).getState() != Thread.State.TERMINATED) {
done = false;
break;
}
}
Thread.sleep(1);
}
timePassed = System.currentTimeMillis() - timePassed;
timePassed = ((double) timePassed) / 1000;
// Thread.sleep(1000);
// Global.printArray(a, N, "Sorted array");
// Global.isArraySorted(a,N);
Global.timePassed = timePassed;
Global.thcount = thcount;
}
void quicksort(int[] a, int lb, int ub) {
int i, j, temp;
int pivpos, pivot;
if (lb < ub) {
i = lb;
j = ub;
// pivpos = ((int)(Integer.MAX_VALUE*Math.random()))%(ub-lb+1) + lb;
// temp = a[lb];
// a[lb] = a[pivpos];
// a[pivpos] = temp;
pivpos = lb;
pivot = a[pivpos];
if (PRINTING)
System.out.println(
"I am handling indices: "
+ lb
+ "-"
+ ub
+ "; I chose pivot as a["
+ pivpos
+ "]="
+ pivot);
while (i < j) {
i++;
while (i <= ub && a[i] < pivot) i++;
while (j >= lb && a[j] > pivot) j--;
if (i < j) {
temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
temp = a[j];
a[j] = a[pivpos];
a[pivpos] = temp;
// if there are too many elements, partition the array and assign it to threads.
// if not, then just do it recursively
int leftPartitionLB = lb, leftPartitionUB = j - 1;
if (leftPartitionUB - leftPartitionLB > minElementsToCreateNewThread) {
if (PRINTING)
System.out.println(
" I am thread("
+ lb
+ "-"
+ ub
+ "), "
+ "and I'm making a new thread for indices "
+ "("
+ leftPartitionLB
+ "-"
+ leftPartitionUB
+ ")");
quicksortThread qsth =
new quicksortThread(
a,
leftPartitionLB,
leftPartitionUB,
this.minElementsToCreateNewThread,
this.PRINTING);
Global.allThreads.add(qsth);
qsth.start();
} else quicksort(a, leftPartitionLB, leftPartitionUB);
int rightPartitionLB = j + 1, rightPartitionUB = ub;
if (rightPartitionUB - rightPartitionLB > minElementsToCreateNewThread) {
if (PRINTING)
System.out.println(
" I am thread("
+ lb
+ "-"
+ ub
+ "), "
+ "and I'm making a new thread for indices "
+ "("
+ rightPartitionLB
+ "-"
+ rightPartitionUB
+ ")");
quicksortThread qsth =
new quicksortThread(
a,
rightPartitionLB,
rightPartitionUB,
this.minElementsToCreateNewThread,
this.PRINTING);
Global.allThreads.add(qsth);
qsth.start();
} else quicksort(a, rightPartitionLB, rightPartitionUB);
}
}